The advent of the wheelchair lift some years ago has provided wheelchair users access to vehicles which increased their mobility and permitted them to take part in a more self-reliant, fully functional lifestyle. A principal type of lift particularly useful with sliding door vans is the rotary type lift. In these lifts, the wheelchair user rolls onto a platform which is then vertically lifted adjacent the side of the van. Once the platform is at the floor level of the van, it is rotated 90 degrees into the van, whereupon the wheelchair user can roll off the platform in the interior of the van and take a position as a passenger or driver of the van.
Present commercially available types of lifts (such as the ABC brand lift, the Golden Boy brand lift, the Collins "Swing Lift" and the Drive-Master brand lift) are all variations on a "basket type" lift. That is, such lifts have a platform or pan suspended from a basket-type handle space above and spanning the platform. The basket handle has two vertical risers, one on either side of the platform connected by a horizontal cross-member spaced above the lift platform. The horizontal cross-member serves as a handrail, permitting the wheelchair user to hold onto the lift while it is being moved vertically and rotated into or out of the van.
The horizontal handrail in such commercially available basket lifts also serves as the principal horizontal support member from which the platform is suspended. As the platform is lowered, it becomes suspended below the lower end of the lift mechamism mounted in the van. In the Collins Lift, for example, one of the vertical riser support members suspended from the horizontal structural handrail is guided by a fixed roller located adjacent the lower end of the lift mechanism mounted in the van.
All of these structures suffer from various amounts of side sway when the suspended wheelchair platform drops below the lower end of the lift mechanism mounted in the vehicle during vertical travel. In instances where the vehicle is not parked on level ground, such as in sloped parking, the platform pan or vertical riser can actually strike the side of the vehicle and damage the vehicle or the lift. In extreme cases it may bind and prevent proper vertical travel of the lift. This is particularly the case when the platform is loaded, with user plus wheelchair weighing on the order of 200-450 lbs.
Further, when the lift is then rotated into the van, the horizontal bar and the two risers remain in a fixed position. The horizontal bar remains fixed and is spaced approximately three feet above the floor of the van. This prevents free access into the van and restricts full usage of the van by able bodied users such as support personnel, family members or drivers. The van thus becomes single-use dedicated, i.e. dedicated to wheelchair use. Such use limitation may be a severe economic hardship to most families.
Still further, VA certification for wheelchair lifts requires certain platform sizes and load carrying capacity, among other lifting characteristics. It has become necessary to beef up lifts in order to meet the needs of increasingly sophisticated certification requirements. For the basket type of lifts this means that the handrail structural support assembly becomes heavier, and the access and free usage of the van is even further restricted.
Accordingly, there is a need in the art for a wheelchair lift which is safe, economical and permits complete vehicle access without restrictions against multifunctional vehicle use. There is a need in the art for a wheelchair lift which is able to carry the increased load requirements of modern day usage, and which is safe, stable and has a relatively low sway when the platform pan is moved vertically below the lower end of the lift. There is a need in the art for such lifts to be able to accomodate an increasingly wide variety of sizes of wheelchairs, both manual and motorized, of various makes, models and types. There is further need in the art to provide a safety handrail which does not restrict vehicle access for able bodied users.